GoF - Behavioral - State

• UML Diagram
• State orquestration
• Pros and Cons
• References

UML Diagram

State orquestration

The state pattern isn't opinionated about how the state is orquestrated. We can implement it in three different ways:

• Orquestrated by the context: The context is responsible for changing the state.
• Orquestrated by the state: The states are responsible for changing the state to another state/next state.
• Orquestrated by client: The client is responsible for changing the state. The usualy pass the context as a parameter to the state.

Pros and Cons

• ✅ Clean code
• ✅ Single Responsibility Principle
• ✅ Open/Closed Principle
• ✅ Easy to add new states
• ❌ Overkill for simple cases (When there are only a few states)

References

• doFactory
• Other Design Patterns